Thomas Powers makes a compelling case that a U.S. attack on Iran would be folly. The day after his article was finished, Israel 'rehearsed an attack on Iran'. Mike Mullen has warned of a 'third front' for US, but is ambiguous about Israel's posture.
It may be that, despite the best efforts of some in the Pentagon and elsewhere, the U.S. administration remains inextricably linked to unhinged and vindictive folly on the part of its key ally and will, as Robert Gates has reportedly predicted, "create generations of jihadists [so that] and our grandchildren will be battling our enemies here in America."
P.S. update 17:02 - an analysis here.